Plugin Idea for devs with time on their hands

[cymatics]

I thought it might be interesting to have a plug that duplicates the variable rise time feature on the Groove Tubes VIPRE.

Would this be difficult? Is this already a feature of a plug that I'm not aware of?

Any input would be appreciated.


- jon

[ohm]

rise time = slew rate. AFAIK slew rate is the amount of time it takes for a signal to change. Older equipment has a high slew rate so high frequencies are cut off and the attacks are smoother. You can use a lopass filter or a transient shaper like a compressor or digitalfishphones dominion (http://www.kvraudio.com/get/878.html) for this. Perhaps a combination?

[Aleksey Vaneev]

I thought it might be interesting to have a plug that duplicates the variable rise time feature on the Groove Tubes VIPRE.

How does it sound?

[stefancrs]

From the manual:

The Vipre features special tube circuitry that allows
the user to adjust the rise time from slow to fast, in
five steps. The FAST setting corresponds to the slew
rates of modern preamplifiers (6 volts per
microsecond), while the SLOW setting is more typical
of vintage equipment (.75 volts per microsecond).
The effect, especially on a large-diaphragm vocal
microphone, is like that of a time machine—the slower
the rise time, the more it will sound like 1950.
Another way of looking at it is that FAST preserves
the full percussive and forward qualities of the source,
while SLOW helps tame overly aggressive sound
qualities and "rounds out" or "smoothes" the material.

http://www.groovetubes.com/product.cfm?Product_ID=1602

I somehow get the feeling that an adjustable envelope follower would be more suitable than a lowpass filter, but I'm note quite sure what they use this rise time setting for yet. I will have a look at the block diagram (also found at the page).

[cymatics]

rise time = slew rate. AFAIK slew rate is the amount of time it takes for a signal to change.

My cursory knowledge of electronics is insufficient to offer a proper explanation of the difference between rise time and slew rate. Suffice it to say the two are related, but not the same.

Older equipment has a high slew rate so high frequencies are cut off and the attacks are smoother.

Actually it would be a slower rise time & not all old equipment exhibits this characteristic

You can use a lopass filter or a transient shaper like a compressor or digitalfishphones dominion (http://www.kvraudio.com/get/878.html) for this. Perhaps a combination?

Simply filtering hi freqs will not reproduce the effect of a slow rise time (or slew rate for that matter). It would be a stretch to get a compressor to reproduce this effect. As you said, a transient shaper would be close to this effect as it is most noticeable on high frequency transient information. However, I don't think it is the same as affecting a signal's rise time. I would defer to someone like Kingston for confirmation though.

[cymatics]

I somehow get the feeling that an adjustable envelope follower would be more suitable than a lowpass filter, but I'm note quite sure what they use this rise time setting for yet. I will have a look at the block diagram (also found at the page).

Thanks Stefan! My knowledge of electronics is just enough to get me into trouble, so I would welcome any input from the more knowledgeable folks here.

[TrevorMag]

My cursory knowledge of electronics is insufficient to offer a proper explanation of the difference between rise time and slew rate. Suffice it to say the two are related, but not the same.

They are just two different ways of expressing the same fundamental property. Lots of distortion and amp sim plugins have this, including mine